Treating human hair



United States Patent inventors Jerzy Josef Bartoszewicz Twickenham; Miklos Moshe Breuer, North Harrow; John Trevor Pearson, Whitburn, England Appl. No. 627,612 Filed April 3, 1967 Patented Oct. 13, 1970 Assignee Lever Brothers Company New York, New York a corporation of Maine Priority April 18, 1966 Great Britain,

TREATING HUMAN HAIR ll Claims, No Drawings US. Cl 132/7, 424/72 Int. Cl A45d 7/04 [50] FieldofSearch l32/7,9; 260/1 17; 424/70. 71, 72

[56] References Cited UNITED STATES PATENTS 2,876,78l 3/1959 Martin.....

3,l98,781 8/l965 Benesch 3,242,052 3/1966 Sheffner Primary Examiner-Louis G. Mancene Assistant Examiner-Gregory E. McNeil] Att0rney-Louis F. Kline, Jr.

applying thereto hydrogen peroxide solution.

TREATING HUMAN HAIR This invention relates to methods for changing the configuration of human hair. Such methods include the waving as well as straightening of hair.

The usual method of waving hair involves treating the hair with amonium thioglycollate solution. This reagent. however, causes considerable damage to hair and consequently frequent application of it is out of the question. It is usually recommended thatthere should be at least a 3 months interval between successive waving treatments with ammonium thioglycollate.

It has now been found that hair waved using. as hair waving agent, an aqueous alkaline solution of homocysteine thiolactone (2-amino-4-mercapto-butyric acid -thiolactone) or a salt or N-substituted derivative thereof (which materials are referred to for convenience hereafter as homocysteine thiolactone compounds) is damaged much less than is the case when the conventional alkaline thioglycollate solution is used. This means that a persons hair can be restyled more frequently. Other important practical advantages in using a homocysteine thiolactone compound is that there is not the strong unpleasant smell that accompanies the use of thioglycollate and further it is less irritant to the human skin than ammonium thioglycollate.

Accordingly the present invention provides a method of changing the configuration of human hair, which comprises contacting the hair with an aqueous alkaline solution of a homocysteine thiolactone compound, confining the hair in a desired configuration, and subsequently subjecting the confined hair to oxidising conditions.

Examples of N-substituted derivatives of homocysteine thiolactone which may be employed are those containing carbonyl groups for example N-alkanoyl groups such as lower (C 1 to C N-alkanoyl groups, N-aroyl groups such as N-benzoyl, and N-(alkyl-aroyll-groups such as N-toluoyl and N-(ethylbenzoyll-groups. As illustrative of salts of homocysteine thiolactone which can be used is mentioned the hydrochloride salt.

The homocysteine thiolactone compound is required to act on the hair under alkaline conditions and this is most conve niently done by applying a mixture of a suitable base and the homocysteine thiolactone compound to the hair. However, if desired, a solution of the homocysteine thiolactone compound and base may be applied to the hair separately. The hair may be contacted with the alkaline solution of the homocysteine thiolactone compound either before or after the hair has been confined in the desired configuration. When applying the homocysteine thiolactone compound in alkaline solution, the solution is desirably one freshly'prepared: it is preferred to apply the solution within about l5 minutes of preparation and for best results within about 5 minutes.

Examples of bases which may be used to impart the necessary alkalinity to the solution of the homocysteine thiolactone compound are inorganic hydroxides, for example sodium hydroxide, potassium hydroxide, calcium hydroxide, ammonium hydroxide; lower alkylamines: alkenolamines, for example monoethanolamine, isopropanolamine, diethanolamine, triethanolamine, and 2-mino-2-methyl-propanl, 3-diol; guanidine carbonate; and morpholine. To minimise the possibility of the base causing skin damage, the pH of the solution is desirably not more than about 1 l and is preferably from about 8 to about 10.

Suitable amounts of the homocysteine thiolactone compound dissolved in the solution are from 5 to 30 percent, preferably to percent, by weight of the solution.

After a person's hair has been confined in the desired manner, such as by winding it on rollers, it will be required to leave the hair in this condition for a certain time to permit the solution of the homocysteine thiolactone compound to soften the hair to the necessary extent. The time required will depend on a number of factors, for example the concentration of the solution of the homocysteine thiolactone compound and also on whether this solution is applied to the hair before or after confining it in the predetermined configuration, and it may also vary from one persons hair to another. Usually, however, it will not be necessary to leave the hair for more than about minutes and in certain cases this time need only be about 10 to T5 minutes or even less.

After rinsing the hair. the next stage of the treatment in accordance with this invention is, as in the conventional thioglycollate process, an oxidation stage. The oxidation of the hair which has been Chemically reduced by contact with the solution of the homocysteine thiolactone compound can be performed by prolonged exposure of the hair to the air or by brief contact with a solution of an oxidising agent, such as hydrogen peroxide, sodium bromate or sodium'perborate.

The solution of the homocysteine thiolactone compound may contain various other ingredients such as wetting agents, buffering agents, swelling agents, opacifiers and thickening agents.

A preferred manner of making up the alkaline solution of the homocysteine thiolactone compound is to mix the homocysteine thiolactone compound eitheras powder or aqueous solution, with a base solution of pH from 9 to l 1.0. Illustrative of acids which can be used to adjust. if necessary, the pH of the base solution to be within the preferred range. are organic acids, for instance lactic, succinic, citric and acetic acids. It has been found that if the homocysteine thiolactone compound is mixed with the solution of the base which has a pH in the above range of 9 to II, then the subsequent treatment of the hair with the mixture leaves the hair in particularly good condition. A good texture or body results and the general appearance of the hair, especially'the gloss, is noticeably good.

The homocysteine thiolactone compounds can be used in either of their optically active forms or as their racemic mixtures.

Some hair waving experiments which were performed in the laboratory on switches of hair to compare the waving performance of homocysteine thiolactone compounds with ammonium thioglycollate will now be described. 1

Switches of 30 cm. virgin hair of approximately l.l were completely damped with water and then lightly blotted. The waving solution (freshly prepared in the case-of thethiolactone compound) was applied to the switch which wasthen wound onto a 1.6 cm. diameter roller and secured with clips. To ensure constant tightness, all switches were wound under a 200 g. tension (Le. by attaching a 200 g.-weight to the end of the switch whilst winding on the roller). When the switch had been secured, it was redamped with the waving solution, and left for 20 minutes, the amount of the waving solution in contact with the hair during this processing time being about half the weight of the hair. After the 20 minute processing time, the switch was rinsed for 3 minutes whilst still remaining on the roller. After rinsing, and neutralising with hydrogen peroxide solution which was applied directly to the hair and left for 10 minutes, the switch was again rinsed for 3 minutes, blotted lightly with a towel and dried under a drier for 30 minutes.

When dry, the switch was allowed to cool on the roller for 5 minutes, then removed and prepared ready for a load cycling experiment on an lnstron Extensometer.

The waving performance of the waving solutions tested were compared by determining for the hair switches treated'as above the lnstron Extensometer equilibrium value (E.V.), which is a measure of the force required to stretch a curled switch a predetermined distance. The lnstron Extensometer equilibrium value was also determined for hair switches treated in the above manner using as the waving solution a standard conventional ammonium thioglycollate solution. The curl retention value for switches'treated with the thiolactone shampooing and rinsing the hair. and the hair was then wound on half-inch. open mesh rollers. The remainder of the solution E.V. for switches treated with thiolactone waving solution Curl Retention Value= E.V. for switches treated with thioglycollate waving solution Example I A waving solution (pH 8) was made up by dissolving 8 g. of N-acetyl homocysteine thiolactone powder in 42 ml. ofa saturated solution (pH 12.4) ofcalcium hydroxide.

This waving solution gave a curl retention value of 85.

Example 2 A waving solution (ph 8.4) was prepared by adding a solution of 7.75 g. of homocysteine thiolactone hydrochloride in 22.25 g. of water to a base solution (pH 10.5) consisting of 5.2 g. monoethanolamine, 2.0 g. lactic acid and 12.8 g. water.

This waving solution gave a curl retention value of 80.

Example 3 A waving solution (pH 9.5) was prepared by adding a solution of 8.0 g. of N-acetyl homocysteine thiolactone in 22.0 g. of water to a base solution (pH 10.5) consisting of 5.2 monoethanolamine, 2.0 g. lactic acid and 12.8 g. water.

This waving solution gave a curl retention value of 80.

Example 4 A waving solution (pH 9.1) was prepared by adding 8 g. of N-acetyl homocysteine thiolactone to a base solution (pH 10.2) consisting of 5.2 g. monoethanolamine. 1.7 g. succinic acid and 35.1 g. water.

This waving solution gave a curl retention value of 75.

Example 5 A waving solution (pH 9.2) was prepared by adding 8 g. of N-acetyl homocysteine thiolactone to a base solution (pl-1 9.5) consisting of 6 g. 2-amino-2-methyl-propan-l, 3-diol, 2.5 g. lactic acid and 33.5 g. water..

i This waving solution gave a curl retention value of 90.

Some comparative experiments which were performed to compare the waving effects produced by N-acetyl homocysteine thiolactone with those produced by N-acetyl cysteine, are reported below.

In one pair of comparative experiments the waving solution consisted of l M of active ingredient and 1.75 M of monoethanolamine.

The solution based on N-acetyl cysteine as active ingredient gave a curl retention value of 70 whereas that containing N- acetyl homocysteine thiolactone gave a curl retention value of 85.

In another pair of comparative experiments the waving solution used consisted of 1 M of active ingredient, 1.75 M monoethanolamine and 0.4 M lactic acid.

The solution based on N-acetyl cysteine as active ingredient gave a curl retention value of 55 whereas that containing N-acetyl homocysteine thiolactone gave a curl retention value of 80.

These experiments clearly show that N -acety1 homocysteine thiolactone produces a stronger wave than N-acetyl cysteine.

Example 6 This example of waving hair was performed in the salon.

5.2 g. of monoethanolamine and 2.0 g. of lactic acid (88 percent solution) were dissolved in 34.8 g. of water; the pH of the solution was 10.4. In this solution 8.0 g. of N-acetyl homocysteine thiolactone were dissolved. The resulting waving solution had a pH of 9.2. Immediately after preparation, part of the waving solution was applied to a head of hair, after first was then applied to ensure saturation of the wound hair. After leaving the hair for 20 minutes. it was rinsed and a solution of hydrogen peroxide then applied to oxidise the hair. The hair. while still wound on rollers, was rinsed again and then dried: a natural soft wave was obtained on brushing out the hair.

Chemical treatments tend to affect the mechanical properties of hair and the reduction in breaking load can be taken as an indication of the extent of hair damage. In the following experiments was measured the breaking load of hair after successive treatments with a waving solution based on a homocysteine thiolactone compound and for comparison similar data were obtained for hair treated with a conventional ammonium thioglycollate solution.

Virgin ltalian Blue String hair was made up into small switches (about 1 g.) and waving solution applied. The hair was then left for 20 minutes, the amount of the waving lotion remaining in contact with the hair during this time being about one-fifth of the weight of the hair. After rinsing, the hair was treated with hydrogen peroxide solution for another 10 minutes. It was then rinsed and dried.

The waving solution based on a homocysteine thiolactone compound had the following composition:

Percent w./w.

N-acetyl homocysteine thiolactone Monoethanolamine Lactic Acid Water The waving solution based on ammonium thioglyco1- late had the following composition:

Percent w./w. Thioglycollie acid 10. 0 Ammonia 3. 1 Wetting Agent 2. 5 Water to 100. 0

Each individual hair (there were about 20 per switch) was then stretched to its breaking point on the lnstron Extensometer and the average breaking load determined. The results are These results clearly show that the treatment of hair with a solution of a homocysteine thiolactone compound causes appreciably less mechanical damage than a thioglycollate solution.

the hair after the repeated treatments with the solution of the homocysteine thiolactone compound was much superior to that of the hair treated with the thioglycollate solution; hair treated with the thioglycollate solution had a very coarse rough feel.

A preferred way of supplying to the user the chemicals to be employed in the method of the invention is by providing in combination in one pack a container of a supply of a homocysteine thiolactone compound (either as a powder or as an aqueous solution) and in a separate container a supply of 5' solution of a base having a pH of at least 9 which when mixed together give an aqueous alkaline solution of the homocysteine thiolactone compound suitable for use in the method of the invention, and optionally in a further separate container a supply of an oxidising agent.

We claim:

homocysteine thiolactone.

3. Method as claimed in claim 1 wherein the hair-treating agent is an aqueous alkaline solution of N-acetyl homocysteine thiola'ctone.

4. Method as claimed in claim 1 wherein the hair-treating agent is an aqueous alkaline solution of homocysteine thiolactone hydrochloride.

5. Method as claimed in claim 1 wherein the hair-treating agent has a pH ofupto ll.

6. Method as claimed in claim 1 wherein the hair-treating agent has a pH offrom 8 to ll.

7. Method as claimed in claim 1 comprising the step of preparing the hair-treating agent by adding the said compound to an aqueous solution ofa base having a pH of from 9 to l l.

8. Method as claimed in claim 1 comprising the step of preparing the hair-treating agent by adding the said compound to an aqueous solution of monoethanolamine adjusted to pH 9 to l l with lactic acid.

9. Method as claimed in claim 1 wherein the hair-treating agent contains from 5 to 30 percent by weight of the said compound.

10. Method as claimed in claim 1 wherein the hair-treating agent contains from 15 to 20 percent by weight of the said compound. 7

11. Method as claimed in claim 1 wherein the hair-treating agent is prepared by forming a 5 to 30 percent by weight solution of N-acetyl homocysteine thiolactone in an aqueous alkaline solution having a pH of from 9 to l l. 

